1. Technical Field
The present invention relates to a printing apparatus that includes a suction hole adsorbing and supporting a printing medium in a printing medium support unit supporting the printing medium supplied to a print execution area and a recess portion receiving and recovering ink discarded upon executing marginless printing.
2. Related Art
An ink jet printer which is an example of a printing apparatus will be described below. Among ink jet printers, there is an ink jet printer including a suction groove adsorbing and supporting a printing medium (hereinafter, also referred to as a “sheet”) in a printing medium support unit (hereinafter, also referred to as a “sheet support unit”) supporting the sheet supplied to a print execution area in order to stabilize the position of the sheet, as disclosed in JP-A-2007-98936 and JP-A-2008-254218.
Among ink jet printers, there is an ink jet printer capable of executing so-called marginless printing on the entire print surface of a sheet. In such an ink jet printer, ink receiving portions (recess portions) are disposed to receive and recover the ink discarded at the positions corresponding to the standard size of a sheet upon executing the marginless printing (see JP-A-2008-254218).
The suction groove may have various forms, as disclosed in JP-A-2007-98936 and JP-A-2008-254218, but the configuration and function of the suction groove are not considerably different between apparatuses. The sheet is adsorbed and supported by the suction force from the suction hole formed in the bottom of the suction groove and a negative pressure generated by blocking of the upper surface of the suction groove by the sheet supplied onto the suction groove.
The ink is received in the way disclosed in JP-A-2008-254218. A recovery opening is formed on the bottom of the ink receiving portion, and the opening is connected to a suction source via a communication passage. The ink possibly discarded in the ink receiving portion is received and discharged by a negative pressure suction force of the suction force, and is guided to a waste ink storage portion. Since the negative pressure suction force is applied to the ink receiving portion, the sheet sent onto the ink receiving portion is adsorbed and supported by the negative pressure.
In an ink jet printer including a sheet supporting unit having the suction hole and the ink receiving portion which is not connected to the suction source, the sheet may not be adsorbed and supported in the ink receiving portion. For this reason, the suction force applied to a sheet which may vary in size may become unbalanced in a sheet width direction. This is because since most of the ink receiving portions are disposed on the side of an individual edge opposite to a reference edge used to position the sheet in the sheet width direction, a difference in the suction force between the reference edge of the sheet and the individual edge is increased with an increase in the size of the sheet.
When the suction force is unbalanced, as mentioned above, the sheet supported on the support surface of the sheet supporting unit may be skewed (inclined) or the sheet in the ink receiving portions may not be sufficiently adsorbed or supported. Therefore, a problem may arise in that the sheet floats or the like. Moreover, print execution quality may deteriorate or the sheet may not be transported appropriately.
On the other hand, since the suction force of the suction source is applied to the ink receiving portion via the long communication passage and the opening in the configuration (see JP-A-2008-254218) in which the ink receiving portion is connected to the suction source via the opening, the negative pressure necessary for the ink receiving portion is hardly generated. Moreover, a problem may arise in that the opening may be narrowed since the ink near the entrance of the opening may dry and stick.